Generation of magnetic fields can be split up into two methods, permanent magnets and electromagnets, including superconducting magnets. For Nuclear Magnetic Resonance Spectroscopy (other applications as well, such as semiconductor characterization), it is desired that as high a static magnetic field be present as possible because signal strength is proportional to the field strength. While superconducting magnets can generate field strengths up to 20 Tesla, they are extremely expensive and large in size. Further, superconducting magnets typically require a super-cooled environment, e.g. about 4.2 K using liquid helium. Electromagnets can be made quite small, but to obtain large fields, a great deal of current must be used. With large currents, excessive heat can be generated in the windings. This heat generation can adversely affect NMR devices because the nuclear magnetic signal is inversely proportional to temperature. Additionally, electromagnets must be driven by an electrical power source.
As such, systems and materials capable of achieving high magnetic field strengths which are relatively inexpensive and suitable for use in practical applications continue to be sought through ongoing research and development efforts.